First male birth control pill: poison arrow extract could be key
Ouabain, a toxin used in Africa in arrow poison, is used in minute quantities to treat heart attacks. Scientists have used a variation to prevent rats’ sperm from swimming. Also in the news: hot or cool, yoga has the same health benefits
To produce the first-ever male birth control pill, scientists have discovered that a plant extract once used by African warriors as a heart-stopping ingredient in their poisonous arrows could be the key.
The natural product is called ouabain and it’s found in two plants native to Africa – the Acokanthera schimperi, or “arrow poison tree”, and the Strophanthus gratus, more commonly known as climbing oleander.
Ouabain is a toxic substance that can cause damage to the heart tissue and lead to death, but when used in much smaller doses it’s found in drugs prescribed by doctors to help control blood pressure and treat heart attack patients.
Researchers at the American Chemical Society noted that ouabain has been shown to curb fertility in men but its high toxicity levels make it unsuitable for this purpose. The scientists created a new ouabain analogue – a variation of the compound with a slightly different molecular structure – that is designed to hone in on a specific protein in sperm that controls its ability to swim. If sperm cells aren’t able to swim, they can’t reach and fertilise an egg.
The team tried out the ouabain compound on rats and discovered that it made them infertile but also proved safe to the animals’ overall health, the study published in The Journal of Medicinal Chemistry said. The scientists also believe that the effects of the pill are completely reversible, like the widely used female birth control pill. New sperm cells were not affected once ouabain left the rats’ systems.
This potential male birth control pill has not been tested on humans but the research is an encouraging step toward levelling the playing field of male and female contraceptive options.
Tribune News Service
Hot yoga no better than cold
Practised in rooms heated to 40 degrees Celsius (104 degrees Fahrenheit), Bikram yoga is no better for your health than other, cooler forms of the ancient discipline, scientists said on Friday.
Proponents claim the hot, humid workout, which puts sweaty participants through a series of 26 poses, burns more calories than yoga performed at room temperature, and is better at flushing out toxins.
Others have pointed to potential dangers such as dehydration and heatstroke.
A study published in the journal Experimental Physiology found that yoga was beneficial regardless of whether it was done in a hot room or at ambient temperature.
Both forms reduced changes in the lining of blood vessels that can lead to heart disease, and appeared to delay the progression of plaque build-up in arteries that can cause heart attacks or stroke.
The findings highlight yoga’s effectiveness “in the absence of a heated practice environment, in improving vascular health,” the study authors write.
The findings were important, they add, “given the increased propensity toward heat intolerance in ageing adults.”
The team enrolled 52 “sedentary but apparently healthy” adults aged 40 to 60 for the trial.
They were divided into three groups, two of which did yoga three times a week for 12 weeks, and a third “control” group which did none.
One of the yoga groups exercised in a room heated to 40.5 degrees, the other at 23 degrees.
“The heated environment did not seem to play a role in eliciting improvements in vascular health with bikram yoga,” says study co-author Stacy Hunter of Texas State University.
New engineered flu virus shows promise for vaccine
Experiments in lab animals have shown signs of success for a newly engineered flu virus that may lead one day to a more effective vaccine, say researchers.
Trials in humans are still a long way off, but the report in the US journal Science earned praise from experts who described it as a promising first step toward better prevention of the flu.
The World Health Organisation considers the flu a major public health concern because it infects up to five million people with severe illness each year and causes up to 650,000 deaths.
“Because the variations of seasonal influenza viruses can be unpredictable, current vaccines may not provide effective protection against them,” says senior author Ren Sun, a professor of molecular and medical pharmacology at the David Geffen School of Medicine at UCLA.
“Previous pandemics and recent outbreaks of bird flu highlight the need to develop vaccines that offer broader, more effective protection.”
Scientists arrived at the new approach by studying the genome of the flu virus and finding eight locations where they could disable its interferon-evasion functions, which affect whether a host can fight the illness or not.
Regular flu viruses are known for their ability to evade the immune system, but this engineered virus showed it “is hypersensitive to one of the body’s primary immune defence mechanisms,” says the report.
The mutant virus can “escape type 1 interferon (IFN-1) function, the body’s first line of defence against viruses.”
The engineered influenza virus “induced strong immune responses” in mice and ferrets without causing them to become ill, says the report.
It also protected against infection by different strains of the flu virus.
More animal studies are planned before any vaccine based on the approach can be tried in people.
Jonathan Ball, professor of molecular virology at the University of Nottingham, describes the paper as a “neat bit of science”.
“There’s still lots of work to do to move this exciting development down the vaccine development pipeline,” says Ball, who was not involved in the research.
“These experiments were performed in laboratory animals and the proof of the pudding will be how the mutant virus performs in humans, especially those who have been exposed to multiple strains of virus and might already have built up a degree of immunity.”
Peter Openshaw, professor of experimental medicine at Imperial College London, describes the work as a “collaborative tour de force between groups in North America and China,” that could lead the way to a universal flu vaccine.
“This advanced approach combines state-of-the-art virology with incisive immunological techniques, potentially leading to greatly improved vaccines in the future,” he says.
However, there are “many hurdles to be overcome moving from pre-clinical through to clinical testing and ultimately to incorporation into standard vaccine schedules.”
Currently, influenza vaccines must be changed every year because the viruses are constantly evolving. Their effectiveness typically ranges from 30 to 60 per cent.